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<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
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<style>
    .box1,
    .box2 {
        width: 300px;
        background-color: red;
        height: 100px;
    }

    .box1 div {
        width: 100%;
        padding: 10px;
        background-color: green;
    }

    .box2 div {
        width: 100%;
        padding: 10px;
        box-sizing: border-box;
        background-color: green;
    }
</style>

<body>
    <h3>1.标准盒模型：尺寸随着轮胎变大而变大，里面尺寸不变</h3>
    <div class="box1">
        <div>标准盒模型</div>
    </div>
    <h3>2.怪异盒模型：尺寸不变，里面尺寸随着轮胎变大而变小</h3>
    <div class="box2">
        <div>怪异盒模型（看到没加padding没有效果）</div>
    </div>
</body>

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